Electric heater



H. E. s'rRUNK ELECTRIC HEATER Driginal Filed Jan.16, 1924 Wm"- F WW umm Il lil" I MWA i110 l,

"14 4-7 His Attorney [lill/Ill PatCntCd lo,

UNITED s'rinasl i PATENT OFFICE.

HARRY E. STBUNK, OF ONTARIO, CALIFORNIA, ASSIGNOR TO EDISON ELECTRIC .AP-

PLIANCE COMPANY, INC., OF

CHICAGO, ILLINOIS, A CORPORATION 0F NEW YORK.

ELECTRIC HEATER.

Application led January 18, 1924, Serial No. 686,623. Renewed November 8, 1987.

My invention relates to electric heaters,

articularly to means for protecting electric heaters from over heating, and has for its object the provision of improved means of this character. v

My invention has particular application to electric liatirons, although obviously it has various other applications.

More specifically, my invention relates to protective devices 1n which a fusible metal or alloy is employed for securing a switch holding member which isreleased upon the fusing of the alloy whereby the heating circuit is opened. As sometimes used, the fusible alloy is held in a suitable container into which the switch holding member extends so as to be embedded and secured in the alloy. Suchl arrangements have the disadvantage, however, that the switch holding member may be loosened due to shrinkage of the alloy in cooling. Also there is a tendency for the switch holding member to creep in the alloy.

In carrying out myinvention, I provide suitable anchoring means for the switch holding member whereby looseness and creeping are prevented.

For more complete understanding of my invention, reference should be had to the accompanying drawing in which Fig. 1 is an elevation view partially in section of an electric flat-iron embodyingmy invention. Fig. 2 is an enlarged plan view of the switching mechanism showing the switch in closed position. Fig.'3 is an enlarged view in section showing the anchoring means for the switch holding member, while Fig. 4 is a sectional view of the line 4 4 of Fig. 3 looking in the direction of the arrows.

Referring to the drawing, I have shown my invention in one form as applied to a well known type of ilatiron comprising a sole plate 10 and a pressurex plate 11 between which is clamped a suitable electric heating unit 12. As shown, the plates are secured together by means of a screw 13. In the sole plate is a circular recess 14 in which is secured a sealed receptacle 15 containing a.

fusible metal or alloy 16. The receptacle 15 is made Vof suitable material such as steel and has its surface oxidized ,or otherwise` treated or protected to prevent amalgamation at high temperature with the fusible metal, for example when the fusible metal is in a molten condition. Extending upward 5I. from the receptacle 15 through an openin 17 in the pressure plate is a stem or switc holding member 18 having a portion 19 of reduced size at its upper end, which portion extends through a suitable aperture in a lever member 2,0 cooperating with the switching mechanism for the circuit of the heating unit 12. The lower end of the stem 18 extends into the receptacle 15 and is embedded in the fusible metal. The stem 18 is thus normally 65 secured inan upright position and when so secured is adapted to hold the switching mechanism in closed circuit position. Upon the occurrence of an excessive temperature resulting in fusing of the' alloy metal, the 70 stem is freed and can tilt to one side to permit the opening of the heating circuit.

Any suitable switching mechanism may be used in the circuit of the heating unit 12. The particular switching mechanism shown is described and claimed in United States Patent #1,439,979 to Earl H. Richardson, dated December 26, 1922, and therefore will not be described in detail. The member 20 is pivotally mounted at its center on a supporting plate 21, which is secured on the top of the pressure plate 11, and is constrained to rotate about its pivot in a clockwise direction as viewed -in Fig. 2 by means of a helical reset spring 22 having one end se- 85 cured to member 20 and its other end secured to plate 21. In the position shown in Fig.

2, the member 2O stands in its extreme posltion in a clockwise direction such that it is brought to rest by the engagement of the stem 18 with a projection 23 kon support 21. The member 2O is held against rotation in a counter-clockwise direction from this position by means of the stem 18, which in turn is secured by the fusible metal, and thus holds the switching mechanism in closed circuit position against the force exerted by a comparatively strong spiral spring 24. This spring has one end 25 secured to supporting plate 21 while its other end is operatively 10 Lesa-47e @i material for which the fusible metal has-no atlinity, such as mica.

While I have described my vinvention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will `suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is

l. A temperature cut-out for electric heaters comprising circuit control means for the heater biased to one position, means for holding said circuit control means in another position, a fusible metal for securing said holding means, a container for said fusible metal, and means for securing said fusible metal to prevent looseness in said container irrespective of the amount of shrinkage of the fusible metal in cooling.

2. A temperature cut-out for electric heaters comprising circuit control -means for the heater biased to one position, means for holding said circuit control means in another position, a fusible metal for securing said holding means, a container for said fusible metal, and means dependent upon the shrinkage of said fusible metal in cooling for holding said fusible metal rigidly in said container when it is solidified 3. A temperature cut-out for electric heaters comprising circuit control means for the heater biased to open circuit position, means for holding said circuit. control means in closed circuit position, a fusible metal for securing said holding means, a. container for said fusible metal, and securing means for the fusible metal comprising a member secured to said container to which said fusible metal clamps itself due to shrinkage in cooling so as to be held immovable with relation to the container.

4. A temperature cut-out for electric heaters comprising circuit control means for the heater biased to open circuit position, means for holding said circuit control means in closed circuit position, a fusible metal for securing said holding means, a container for said fusible metal, and an anchor member secured to said container dividing th'e lfusible metal into two portions and 'provided with apertures through which the portions are connected whereby the fusible metal shrinks tight-ly on said anchor member in cooling so as to be rigidly secured thereby in said container.

5. A temperat-ure cut-out for electric heaters comprising circuit control means forv the heater biased to open circuit position, a member for holding said circuit control means in closed circuit position, a fusible metal for securing Said holding member, a container for 'said fusible metal, and a member embedded in said fusible metal extending trans ber for said circuit control means, a container, a fusible metal in said container, and cooperating anchor members secured recontainer, said anchor members being embedded in said fusible metal whereby said holding member is secured.

7'. A temperature cut-out for electric heaters comprising circuit control means for the heater -biased to one position, a member for holding said control means in another position, a container, a fusible metal in said container, an anchor member secured in said container and embedded in said fusible metal, and means onA said holding member cooperating with said anchor member so as to apply a shearing force to said fusible metal whereby said holding member is secured.

8, A temperature cut-out for electric heaters comprising circuit control means for the:

heater biased to one position, a member for holding said control means in another position, a container, a transversely extending member secured in said container and provided vvith apertures, projections on said holding member adjacent said transversely extending member, and a fusible metal in said container embedding said transversely extending member and said projections so as to secure said holding member.

9. A temperature cut-out for electric heaters comprising circuit control means for the heaterbiased to one position, a pivoted member for holding said circuit control means in another position, a fusible metal securin said holding member, a container for said fusible metal, a flexible diaphragm closin said container forming a pivot for said hol ing member, andmeans for protectin said diaphragm from contact with said usible metal com rising a member secured in andV partially c osing said containery and a member carried by said holding member forming -a tight joint with the first and sliding wit relation thereto upon tilting of said holding member.

10. A temperature cut-out for electric heaters comprising circuit control means Ifor the heater biased to one position, a. pivoted member for holding said circuit control means in another position, a fusible metal securing said holding member, a container spectively to said holding member and said Y for said fusible metal, a exible diaphra closing said container forming the plvot or said holding member, and means for protecting said diaphragm from contact with' said 5 fusible metal comprising a washer secured in said container surrounding said member, and a disc carried by said member cooperating with-said washer to form a tight'joint and sliding with relation thereto upon morement of said holding member on its pivot.

In witness whereof, I have hereunto set my hand this 10th day of January, 1924.

y HARRY E. STRUNK. 

